ASSESSMENT OF CHANGES IN CAROTID BLOOD FLOW FOLLOWING LLLT OF THE NECK

Abstract

There are several reports on improvement of blood flow following LLLT, and reports on actual vessel dilatation and blood flow enhancement has been observed in animal models. However there are no reports on changes in blood flow observed in human subjects using a non-invasive method for any duration of time. In this study, we used non-invasive Doppler color flow imaging to observe changes in the blood flow of the common carotid artery following laser irradiation to the lateral neck region. Laser output- and dose-dependent differences in the blood flow were observed, but there was also an increase in the diameter and cross-sectional area of vessels. Increased blood flow was noted in the common carotid artery of both the irradiated and unirradiated side, which lasted for over 1 hour after laser irradiation. The maximum increase in the crosssectional area, vessel diameter and the blood flow on the irradiated side were 69%, 31% and 63% respectively. On the unirradiated side the maximum increase of the cross-sectional area, vessel diameter and blood flow were 52%, 21% and 71% respectively. There were no changes observed in the maximum, minimum or average blood flow velocity of either the irradiated or unirradiated side.